Noise Induced Hearing Loss (NIHL)
What is Noise Induced Hearing Loss?
Your inner ear contains sensitive hair structures called sterocillia that are affected over the long-term by high decibel sounds which cause Noise Induced Hearing Loss (NIHL). Intense sounds experienced over long periods of time will permanently damage the tiny hairs in your cochlea. We do not have the capacity to regrow cochlear hair cells. Nerve deafness can cause mild, moderate, severe and profound hearing loss. NIHL cannot be medically or surgically improved. It is a disease of our environment. For example, if you live in a noisy city where the decibel level of rush hour traffic is 85 decibels or more, your stereocillia are under assault. You can protect them. Ask an ENT&AA professional how to do it.
What are the symptoms of Noise Induced Hearing Loss?
- Gradual loss of hearing
- Difficulty hearing foreground voices against noisy backgrounds
- Words can drop out of sentences
- Often asking people to repeat sentences
- Some sounds seem shrill or excessively loud
- Difficulty hearing people on phones
- Difficulty hearing some parts of speech
- Plugged feeling in the ear
- Tinnitus or ringing in the ear
What causes Noise Induced Hearing Loss?
Noise induced hearing loss (NIHL) is caused by repetitive exposure to unsafe levels of noise. If you are wondering what an unsafe noise level is, imagine a normal conversation that is safe at 60 decibels. Now increase the decibel level by just 25 dB to 85 dB to approach the danger zone for hearing damage. This level is easy to reach several times a day. The best strategy to take is to shun noises that are too loud, too close or last too long.
Sound Levels in the Environment
- The humming of a refrigerator: 45 decibels
- Normal conversation: 60 decibels
- Noise from heavy city traffic: 85 decibels
- Motorcycles: 95 decibels
- An MP3 player at maximum volume: 105 decibels
- Sirens: 120 decibels
- Firecrackers and firearms: 150 decibels
What can happen if my Noise Induced Hearing Loss is not treated by a doctor?
- Possible loss of hearing
How is Noise Induced Hearing Loss diagnosed by your doctor?
Your doctor will perform a physical exam and examine your ears with an otoscope to identify the health status of your ear canal and eardrum. He or she may ask you to cover one ear at a time to test how well you respond to words spoken at different sound levels.
Tuning Fork Test
He or she may perform a tuning fork test which is an excellent test for determining if your hearing loss is caused by conductive issues; or by problems with your auditory nerve system (sensorineural); or by a combination of both.
The tympanogram which is the output from the tympanometry test will provide the clinician with information on the functional levels of the middle ear, mobility of the ear drum and can help determine if your hearing loss is conductive or sensorineural.
To assess your current hearing status, an audiologist will conduct a series of hearing tests to chart hearing thresholds at a range of frequencies for each ear.
How do you treat Noise Induced Hearing Loss?
- While Noise Induced Hearing Loss has no treatment that can reverse it, NIHL caused by noise is preventable.
- Wear ear protection gear at noisy events like rock concerts or football games. This will help reduce the impact of noise levels on your hearing.
- Move away from loud noise sources to reduce impact on your inner ear.
- When using ear buds or headphones, turn down the volume to safe levels.
- Be alert to hazardous noises in your work and family environments and work to eliminate them.
- Educate your family members, friends and fellow workers by raising awareness about NIHL.
Your hearing tests may indicate that your Noise Induced Hearing Loss is manageable and requires no treatment. Your ENT & AA doctor may suggest that you track your hearing health by having it tested on an annual basis.
There are no medications for curing Noise Induced Hearing Loss, but researchers are experimenting with antioxidant vitamins, vasodilators, Coenzyme Q10 and ebselen to help reduce environmental noise damage to cochlear hairs.
If your hearing loss is severe enough, you and your ENT & AA doctor may consider a cochlear implant which is designed to provide sound signals to your brain via your vestibular cochlear nerve.
Stem Cell Therapy
There are several studies that are using stem cell and gene therapy to regenerate cochlear hair cells to improve Noise Induced Hearing Loss. ENT & AA doctors are following these developments closely, but patients should be aware that the drug development and approval process can take years.